Single-walled carbon-nanotube forest immunosensor for amplified detection of cancer biomarkers

Prostate specific antigen (PSA) is a major biomarker used clinically in the detection of prostate cancer. Current commercial immunoassays for detection of this biomarker rely on spectroscopic absorbance and electro-chemiluminescence which are able to detect as low as 0.03 ng/mL of PSA within 100muL of serum. In this paper, a novel amplified electrochemical technique for detection of prostate specific antigen is described. This electrochemical approach is a highly sensitive method that can have detection limit of 0.004 ng/mL in only 10 mL of serum, a mass detection limit 75 times lower than current commercial techniques. This highly sensitive, low cost and fast detection method not only allows for detection of cancer biomarkers in serum, but also in tissue and cells. Moreover, immunoassay arrays based on this methodology will be highly promising for application in large-scale clinical screening and point-of-care diagnostics. Characterization of the anti-PSA amplification tag in this amplification system using TEM, AFM, SEM, and CE is also described